1. Field of the Invention
This invention relates to a portable GPS navigation device. The navigation device can display travel information and finds particular application as an in-car navigation system.
2. Description of the Prior Art
GPS based navigation devices are well known and are widely employed as in-car navigation devices. Reference may be made to devices that integrate a GPS receiver into a computing device programmed with a map database and that can generate navigation instructions on a display, such as the TomTom Go™ device. These portable, integrated devices are often mounted on or in the dashboard of a vehicle using a suction mount.
Reference may also be made to the Navigator series software from the present assignee, TomTom B.V. This is software that, when running on a PDA (such as a Compaq iPaq™) connected to an external GPS receiver, enables a user to input to the PDA a start and destination address. The software then calculates the best route between the two end-points and displays instructions on how to navigate that route. By using the positional information derived from the GPS receiver, the software can determine at regular intervals the position of the PDA (typically mounted on the dashboard of a vehicle) and can display the current position of the vehicle on a map and display (and speak) appropriate navigation instructions (e.g. ‘turn left in 100 m’). Graphics depicting the actions to be accomplished (e.g. a left arrow indicating a left turn ahead) can be displayed in a status bar and also be superimposed over the applicable junctions/turnings etc in the roads shown in the map itself.
The term ‘navigation device’ refers to a device that enables a user to navigate to a pre-defined destination. The device may have an internal system for receiving location data, such as a GPS receiver, or may merely be connectable to a receiver that can receive location data. The device may compute a route itself, or communicate with a remote server that computes the route and provides navigation information to the device, or a hybrid device in which the device itself and a remote server both play a role in the route computation process. Portable GPS navigation devices are not permanently integrated into a vehicle but instead are devices that can readily be mounted in or otherwise used inside a vehicle. Generally (but not necessarily), they are fully self-contained—i.e. include an internal GPS antenna, navigation software and maps and can hence plot and display a route to be taken.
The present invention provides a ‘hands-free’ mobile telephone capability: in many countries and also states in the USA, it is illegal to drive a vehicle whilst holding a mobile telephone; instead, the telephone must be used without the driver having to hold or directly manipulate any of the controls of the telephone itself. One common approach is for a driver to use a headset that communicates with a mobile telephone over a short range wireless network, such as Bluetooth™. It is also possible to integrate hands-free functionality into a vehicle's sound system; this requires permanent mounting of a microphone near the driver and either a mobile telephone permanently mounted in the car or a wire or wire-based connection from the sound system to the mobile telephone. Such systems can integrate with the functionality of the sound system; for example, automatically muting the vehicle radio if a voice call comes in. But they are very costly.